Cellulose-ether solvent and composition



- will produce dopes of the desiredqualities.

Patented Nov. 7, T922.

UNHTED STATES ens-rarer series.

WILLIAM E. WEBB, OF ROCHESTER, NEW YORK, ASSTGNOR TO EASTMAN KODAK COMPANY, OE ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK.

OELLULOSE-ETHER SOLVENT AND COMPOSITION.

No Drawing;

To all whom it may concern:

Be it known that 1, WILLIAM R. WEBB, a

citizen of the United States of America, residing at'litochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Cellulose-Ether Solvents and Compositions, of which the following is a full, clear, and exact specification.

This invention relates to solvents for making strong solutions of cellulose ether and also relates to the cellulose ether compositions produced by the aid of such solvents. One object of my invention is to provide a solvent which-will dissolve such large proportions of cellulose ethers that thick or viscous flowable solutions may be obtained for use in plastic and film making arts. Another object of my invention is to provide a cellulose either solution which may be manufactured into strong, flexible, transparent film on the machines and by the methods now in use.

In U. S. Patent No. 1,188,376, Lilienfeld, June 20, 1916, there are disclosed a series of alkyl ethers of cellulose. Certain of these are practically insoluble in water, and my invention relates but is not limited to the ethers having that property. I While the ethers form thin solutions in carbon tetrachlorid or in the acetic esters of the lower monohydroxy aliphatic alcohols, it has been found that such single solvents bythemselves will'not dissolve a suficient proportion of the ethers to make a desirably thick, flowable composition or dope, such as may be used for instance in the manufacture of photographic-film base by the customary methods.

I have discovered that an adequately stron by mixing these. substances, and that they s one example of my invention, I may mix 75 parts of carbon tetrachlorid with 25 parts of ethyl acetate ormethyl acetate, or a mixture: of them. The acetic esters of propyl, isopropyhbutyl, isobutyl, amyl, and isoamyl alcohols have a similar action but in lessdegree.

The cellulose ether, such as water-in-' soluble ethyl cellulose, is dissolved in the above mixture. The most useful proportrees are 1 part of cellulose ether by weight and useful solvent may be prepared Application filed February 23, 1922. l Serial No. 535,644.

to 5 parts of the solvent. F or film manufacture, we prefer to employ 1 part of the ether to from 4 to 6 parts by weight of the solvent. From 4 to 6 parts by weight of the separate solvent constituents alone, will not dissolve 1 part of this ether to produce a flowable dope useful in film mahufacture. Other substances which impart suppleness, or incombustibility, or other qualities to the film may be added to the dope, such, for instance as triphenyl phosphate, tricresyl phosphate, camphor, monochlornaphthalene, etc.

The ingredients are of the ordinary com- -mercial type and sulhciently purified for the process of film manufacture, so as to give a dope yielding films having the proper relative freedom from color. The viscousflowable dope above described can be used in connection with the usual film-forming apparatus without the necessity of expensive alterations in the latter.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A mixed solvent for cellulose ether, comprising carbon tetrachlorid and the acetic ester of a monohydroxy aliphatic alcohol of less than 6 carbon atoms.

2. A mixed solvent for cellulose ether, comprising carbon tetrachlorid and ethyl acetate.

3. A mixed solvent for cellulose ether, comprising approximately 75 parts by weight of carbon techrachlorid and 25 parts by weight of ethyl acetate.

4. 'A flowable film-forming composition, comprisin cellulose ether dissolved in a mixture oi carbon-tetrachlorid and an acet1c ester of a monohydroxy aliphatic alcohol of less than 6 carbon atoms.

,5. A fiowable film-forming composition, comprising an alkyl ether of cellulose dissolved in a mixture of carbon tetrachlorid and ethyl acetate.

6. A flowable film-forming composition, comprising water-insoluble ethyl cellulose dissolved in a mixture containing approximately '75 parts by weight of carbon tetrachlorid and 25. parts by weight of ethyl acetate. i Signed this 27th day of January 1922. 

